Slack adjuster



23, 1938'. u y f i JAMES,A JR 2,127,45320 i SLACK ADJUSTER Filed May 20,1937 2 Sheets-Sheet 1 Aug. 23, 938

2 Sheets-l-Shbet 2 ,/ff. riff- 4 42 44 40 was 344g Patented Aug. 23,1938 UNITED STATES PATENT OFFICE N Universal Slack Adjuster Company,Camden,

N. J., a corporation of New Jersey Application May 20, 1937, Serial No.143,690

11 Claims.

My invention relates to improvements in automatic slack adjusters forstandard brake rigging for railway cars.

The object of my invention is to provide a slack adjuster comprising aspreader having a pair of extension piston rods mounted thereon andpivotally associated with a lever of the brake rigging and means forautomatically actuating said rods for taking up slack in the rigging. lA further object is to provide novel means for locking the parts of theslack adjuster in brake release position to insure the parts against anyaccidental movement which would tend to eliminate the proper clearancebetween the brake shoes and the wheels.

A further object is to arrange the piston rods for movement with thelever through different distances, and provide the rod having theshorter travel, with ratchet teeth which are relatively closer togetherthan ratchet teeth upon the other of the rods and having a greatertravel, whereby the ratchet teeth of each rod will be properly engagedby pawls mounted upon the spreader throughout the various positions ofadjustment of the pistons, to maintain the proper angle oi the lever inthe release position throughout the adjustments of the spreader.

A further object is to provide means for readily unlocking the pistonrods from the spreader, in-

cluding extension operating means which may be actuated from the sidesof the ear, thus avoiding the necessity of the operator going beneaththe car to release the brakes when the worn brake shoes are to bereplaced and the adjusting device is to be reset to the startingposition.

These together with various other novel construction and arrangement ofthe parts, which will be more fully hereinafter described and claimed,constitute my invention.

Referring to the drawings:

Fig. 1 is a side elevation, partly in section, of my novel slackadjuster.

Fig. 2 is a horizontal section on line 2 2 Fig. l.

Fig. 3 is a transverse section on line 3-3 Fig. l.

Fig. 4 is a plan View of the lower one oi the pawls shown in Fig. 1.Fig. 5 is a vertical longitudinal section on line 5-5 Fig. 2, showingthe parts with the brakes applied.

5o Fig. 6 is a View similar to Fig. 5 showing the parts in the adjustedposition.

Fig. '7 is a transverse section on line 'I--l' Fig. l.

Referring to the drawings in which like reference characters refer tolike parts, I0 represents V5.5 the pull rod adap-ted to be operated byany standard air brake cylinder or any hand brake device, not shown inthe drawings. A live lever I2"is pivotally connected by a pin I3 withthe rod I0.

A dead .lever I4 is pivotally connected by a pin I5 with a link I6,which is pivoted upon a fixed bear- 5 ing I'I. The opposite end of thelever I4 is connected with one end of a spreader I8, by a pin I9, andthe lever I2 is pivotally associatedwith the opposite end of thespreader I8 by my novel ad# justing device 2D.

Brake shoes 22 and 23 are associated with the intermediate portions ofsaid levers and are adapted to be applied to the wheels 24 and 25,.indicated by dot and dash lines.

The end of the spreader I8 which is associated with the lever I2 isprovided with a housing 25, forming chambers, or cylinders, 2'I and28,*which are square in cross section, and having their longitudinalaxes extending parallel with the length oi the spreader I8. g

The cylinders 2l and 28 are provided with bushings 3II and 3|respectively, whichA a're secured within the cylinders by the wellknownp'ressi'ng operation. Piston rods 34 and 35, preferably o'i squarecross section, areslidably mounted in the bushings 30 and 3|, and areadapted for longitudinal movement relatively to the housingand thespreader I8.

The lower piston rod 34 extends beyond one end of the housing 26 and isprovided with a bi- 30 iurcated head 38 which embraces` the free end ofthe lever I2. Said head v38 is pivotally connected to the lever I2 by across-head 4U. .Guides II- 4I are mounted upon the housing 26 and areprovided with longitudinal slots 42-42, in 35 which the cross-head 401sslidably mounted.

The guides III- 4I comprise upper guide bars 43-43 and lower bars I4-44. The top bearing surfaces 45-45 of the upper bars 43-43 are inclinedfor purposes hereinafter described. 40

The lower piston rod 34 is provided with teeth Ill, forming a rack uponone vertical face thereof. A pawl 48 is located within the housing 26and has a hub 49 which is rotatablymounted upon a pin 50, which in turnis rotatably mounted 45 upon the housing. rThe pawl IIS is urged intoengagement with the teeth 47 of the rack by a spring 5I having one endattached to a lug 52 formed upon the hub 49. The opposite end oi thespring is attached to a pin 53 secured upon the housing. 50 The lowerrod 34 forms a holding rod and the pawl 48, engageable therewith, formsa holding pawl, and they are adapted for holding the rod 34 and thespreader in fixed relation when the pull rod IIl is moved in thedirection of the arrow Fig. 55

1, for moving the levers I2 and I4 for applying the brakes.

The upper piston rod 35 forms an adjusting rod. It extends beyond thehousing 26 and is provided with a bifurcated head 55, which embraces thelever I2, and is pivotally connected with the lever by a ulcrum pin 56.Said head 55 is provided with elongated slots it- 58, which slots extendvertically and are adapted to permit said pin 56 to move verticallyrelatively to the head 55 when the lever I2 is moved in the direction ofthe arrow Fig. l, about the cross-head 46 as a center.

The adjusting piston rod 35 is preferably of square cross-section and isprovided with teeth 60, forming a rack upon one vertical face thereof.An adjusting pawl 6I is located within the housing and is engageablewith the teeth 6l?. The pawl 6I is rotatably mounted upon said pivot pin5D, and is urged into engagement with the teeth 60 by a spring 63attached to a lug 64- on the hub 65 of the pawl 6I, and to a pin 53secured upon the housing.

The pawls 48 and 6I are located in chambers 66 and 61 formed in a sideextension 5B of the housing, and are enclosed by a cover 69, detachablysecured to said extension 68.

The pin 50, on which the pawls 48 and 6l are mounted, projects beyondthe housing and is provided with means for manually releasing the pawlsfrom the racks of the piston rods when it is desired to return thepiston rods within the housing to a starting position. As shown in Fig.2, the hub 65 of the pawl 6l has secured therein a key 1I, and the pawl48, shown in Fig. 4, has a similar key 12.

The pin 50 is provided with a longitudinal keyway 13, as shown in Fig.7. The keys 1I and 12 occupy the key-way 13, and the latter is ofsuflicient width to permit the pawls to rotate on the pin 50 so thatthey can move into and out of the teeth 41 and 60 of the racks of therods 35 and 36 during the ordinary adjustments of the piston rods.

The pin 50 extends above the housing and has secured thereto a doublearm lever 15. Pull rods 16 and 11 are attached to the ends of theopposite lever arms and extend in opposite directions, as shown in Fig.7. The rods 16 and 11 have handles 18 and 19 which are located adjacentto the opposite sides of the car on which the brake rigging is mounted.By pulling either of said handles the pin 50 will be rotated and engagethe keys 1I and 12 and rotate the pawls 48 and El out of engagement withthe racks of the piston rods 34 and and permit said rods to return intothe cylinders of the housing 26, when it is desired to reset the rodsfor the purpose of renewing the brake shoes 22 and 23.

The teeth 60 of the rack on the adjusting rod 35 are spaced closertogether than the teeth 4l' of the rack on the holding rod 34, due tothe difference in the distances through which the fulcrum pin 56 travelsrelatively to the cross-head 4I! during the movements of the lever I2for operating the brakes.

During the normal applications of the brakes the lever I2 moves in thedirection of the arrow Fig. 1, and rotates about the cross-head as acenter. The fulcrum pin 56 withdraws the adjusting piston rod 35 fromthe housing a distance slightly less than one tooth space of the rack onthe rod 35, so that the adjusting pawl El does not engage a new tooth 6Dand the cross-head 453 retains its same position relatively to thehousing 26 and the spreader I8, during said normal applications of thebrakes.

When the pull rod Il! moves through a greater stroke than apredetermined stroke, due to slack in the rigging, or to wear in thebrake shoes, the lever I2 will have an abnormal stroke which will causethe fulcrum pin 56 to withdraw the adjusting piston rod 35 to a positionshown in Fig. 5, which will allow the adjusting pawl 6I to engage a newtooth 50 of the rack on the adjusting piston rod 35, thereby locatingsaid rod 35 in a new position and also the fulcrum pin 56 in a newposition relatively to the housing, so that upon the return movement ofthe lever I2, to release the brakes, the lever will rotate about fulcrumpin 56 and cause the cross-head to withdraw the holding piston rod 34until the holding pawl 48 engages a new tooth 41, as shown in Fig. 6,thereby increasing the eiective length of the spreader and eliminatingany slack in the rigging.

Should there be suicient slack in the rigging to cause the adjusting rod35 to move a distance equal to two or three teeth relatively to theadjusting pawl 6I, then the holding rod 34 will be moved proportionatelyso that the holding pawl 48 will take up the same number of teeth uponthe holding rod 34. Due to the relative sizes of the teeth in the tworods 34 and 35, one rod cannot ride beyond the other, therefore anadjustment of one tooth by the adjusting pawl will adjust the holdingpawl one tooth, and an adjustment of two teeth by the adjusting pawlwill adjust the holding pawl two teeth, and so on until all the slack isremoved from the rigging, when the ordinary strokes of the lever I2 willbe resumed and the adjusting pawl 6I will then ride upon the same toothwithout engaging a new tooth of the piston 35.

By providing the adjusting piston rod 35 with smaller rack teeth thanthe teeth upon the holding piston rod 34, the end of the lever I2, whichis connected with the pull rod by the pin I3, will always return to thesame position when the brakes are released, thereby insuring the pullrod I0 always being located in the full release position.

The head 55, upon the adjusting rod 35, is slidably mounted upon the topsurfaces 45-45 of the upper guide bars 43-43. The head 55 is providedupon the lower portion thereof with depending flanges 811-80, whichextend into the Space between the two parallel bars Pi- 43, for freelyguiding the head 55 in alignment with the length of the guides. The head55 also has enlarged cheek lugs 8I-8I which extend over and rest uponthe top surfaces 45-45 of the top guide bars 43-43. Said cheek lugsill-8| form the head 55 into a locking wedge for securing the parts ofthe adjusting device against accidental movement when the brakes are inrelease position.

Figs. 1 and 6 show the parts in brake release position, and also showthe lugs I-SI locked in frictional engagement with the top surfaces ofthe guide bars 43-43, by the position of the lever I2. The weight of thelever I2, when in the release position of the brakes, tends to iorce thecross-head 40 upwardly against the lower surfaces of the bars 43-43. Thefulcrum pin 55 engages the head 55 at the lower limit of the slots 58and thereby wedges the head 55 upon the top surfaces of the guides43-43, so that the parts cannot move relatively to each other exceptwhen the lever I2 is moved in the direction of the arrow Fig. 1, by thepull rod I0, for applying the brakes. 75

42, such as the lines vin Fig. 1, the lever The `top surfaces 45-45 ofthe guide bars 43-43 are inclined, as shown in Figs. 1, 5 and 6. Thebushing 3| is recessed for the adjusting rod 35 so that the latter isinclined relatively to the length of the housing and parallel with theinclined surfacesd5-45 of the bars 43--43.` By this arrangement, as thecross-head is adjusted to various positions throughout the length of theguide slot position shown in dot and `dash I2 will be inclined at asmaller angle relativelyA to the length of the spreader I8, or to alineextending through the center of the cross-head 40 and the center of thepivot pin I9 for the dead lever I 4. The inclined-surfaces -45 of thebars 43-43 insures the `wedge formed by the head toexactly ll thespacebetween the fulcrum pin 56 and the top inclined surfaces of the guidebars 43-43, as shown' bythe two positions of the lever I 2 and lthe head55 in Fig. 1. Thusat any position of the head '55 throughout the lengthof the guide bars 43-43, the head 55 will form a wedge, or fulcrumblock, upon which the `leverI2 will be supported When in brake releaseposition and thus lock the `parts against accidental movement relativelyto the spreader.

The inclined surfaces 45-45r of the guide bars insure `the return of theend of the lever I2 carrying the pin I3, to the normal release positionregardlessof the position of the cross-head 40 relatively to the lengthof the slot in the guide, thereby'insuring the proper clearance of thebrake shoes;

By. my.` novel adjusting device the' pull rod I0 land the end oflever'IZ carrying the pin I3 can always return to the normal positionwhen the brakes -are released, thereby eliminating the bucklingaof thepull rod I0 when in full release position.

; flengthfof the spreader The'above described means for locking thelever I2 in brake release position also controls the position of thebrake shoes, relatively to the wheels, when the lever I2 is in brakerelease position, and insures a uniform clearance between the brakeshoes and the wheels when the brakes are released.

Various changes in the construction and arrangement of the parts may bemade without departing from my invention.

I claim:

l. Aslack adjuster for brake rigging for railwaycarscomprising a leverhaving a normal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a pair of piston rods slidablymounted upon the spreader and adapted to be extended beyond one end ofthe latter, adjusting means associated with each rod andthe spreader andadapted for inependently holding said rods against movement in onedirection relatively to the length of the spreader, a cross-headpivotally connecting the lever and one of said rods, a fulcrum pinpivotally connecting the lever with the other of said rods and adaptedfor alternately moving said rods relatively to the upon abnormal strokesof the leverfor taking up slack in the rigging, and a guide bar upon thespreader and located be tween saidrods and forming a stop support forthe lever when in brake release position.

2. A slack adjuster for brake rigging for railway cars comprisinga'lever having a normal stroke for the operation of the brakes, aspreader opera-tively associated with the brakes, a pair of piston rodsslidably mounted upon the spreader and adapted to be extended beyond oneend of the latter, adjusting means lassociated `with veachV rod andthespreader adapted for indepenently holding said 'rods againstmovementinonedirection relatively to the length of the spreader,I aycrosshead pivotally connecting the lever'and 4one of said rods, afulcrum pin pivotally connecting the lever with the other-of said rodsand' adapted yto alternately moving said rods relatively to the lengthof the spreader upon abnormal strokes of the leverlfortaking up slackinv the rigging, a

adapted for independently holding saidrodsagainst movement in'onedirection relatively'to the length of the spreader, a cross-headpivotally connecting the leverand one of said Irods, a fulcrum pinpivotally connecting the-lever with `the other of said rods and'adapted'for-alternately moving lsaid rods relatively to the 'lengthofthespreader upon'` abnormal strokesof the lever; and a guide bar upon' thespreader'and located between-said rods and forming' astop vsupport forthe lever when' in brake release position-'and-for limiting theclearance between'the brake shoes and the face of 'the wheels when inrelease position:

4. A slack adjuster forbrake riggingI for-'rallway cars comprising a'rlever havingranormal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a holding piston rod, anadjusting piston rod, a-housing upon the spreader upon Iwhich said rodsare slidably mounted for extension beyond the housing, a guide baruponthe housing and'located between said rods, a= cross-head pivotallyconnecting'the lever with said holding rod and slldablyf mounted uponthe guide bar, afulcrum pin pivotally connecting the lever with saidadjusting rod, said fulcrum pin positioned upon the lever for movementwith the leverV through an'archaving the cross-head-as acenter andadapted toimpi'nge the guide bar between'thecross-head and saidadjusting rodwhen the lever is inclined relatively, to the'length of theguide bar andflin brake release position, and adjusting means associatedwith each7 of said-rods and the housing andV adapted for increasing theelective length of the spreader upon abnormal i strokes of the lever.

5. Aslack adjuster' for brake rigging forrailway cars comprising-'alever having a* normal stroke for the op'erationof the brakes,a-spreader operatively associated with the brakes, a holding piston-rod,an adjusting piston rod, allousing upon the' spreader upon which said'rodsare slidably mounted forlextension beyond the'housing, a guide barupon the housing and'located between said rods, a cross-head pivotallyconnectin'gf the leverwithsaid holding rod-"and-sli'dably mountedupon'the guide bar, abearin'g `head upon said adjusting rod and slidablymounted upon the opposite side of the guide bar relatively to thecross-head, a fulcrum pin pivotally connecting the lever with saidbearing head, said fulcrum pin Lso lthe spreader upon abnormalpositioned upon the lever for locking said adjusting rod relatively tothe g 'de bar when the lever is inclined relatively to the guide bar andin brake release position, and adjusting means associated with each ofsaid rods and the housing and adapted for increasing the effectivelength of the spreader upon abnormal strokes of the lever.

6. A slack adjuster for brake rigging for railway cars comprising alever having a normal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a holding piston rod, anadjusting piston rod, a housing upon the spreader upon which said rodsare slidably mounted for extension beyond the housing, 'a guide bar uponthe housing and located between said rods, a cross-head pivotallyconnecting the lever with said holding rod and slidably mounted upon theguide bar, a fulcrum pin positioned upon the lever for movement with thelever about the cross-head as a center, a bearing head upon saidadjusting rod, said head having an elongated slot formed therein andextending at approximately right angles to the length of the spreader,said fulcrum pin occupying said slot and adapted to engage said headbetween the fulcrum pin and the guide bar and form a stop support forthe lever when in brake release position, and adjusting means associatedwith said rods and the housing adapted for increasing the effectivelength of strokes of the lever.

7. A slack adjuster for brake rigging comprising a pull rod having afixed brake release position, a lever, a pivot pin connecting one end ofthe lever with said rod, a spreader, a guide bar -upon the spreader, across-head upon the opposite end of the lever and movable relatively tothe length of the guide bar, a holding rod slidably mounted upon thespreader and pivotally associated with the cross-head, means forextending the holding rod .relatively to the spreader for taking upslack in the rigging by advancing the cross-head along the guide bar, afulcrum pin upon the lever, a fulcrum head movable by the ulcrum pinalong said guide bar, said guide bar having a bearing surface upon whichsaid head is slidably supported, said bearing surface positioned at anoblique angle relatively to the longitudinal axis of said holding rodfor maintaining a uniform arc between the lever and said bearing surfacewhen the lever is in brake release position throughout the diierentadjusted positions of the cross-head upon the guide bar, and saidfulcrum head forming a stop adapted to be impinged between the fulcrumpin and said bearing surface when in brake release position.

8. A slack adjuster for brake rigging for railway cars comprising alever having a normal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a holding piston rod,l anadjusting piston rod, a housing upon the spreader upon which said rodsare slidably mounted for extension beyond the housing, a. guide bar uponthe housing and located between the portions of said rods extendingbeyond the housing, said rods having their longitudinal axes inclinedrelatively to each other and converging beyond the housing, said guidebar having bearing surfaces extending parallel with the respective axisof each rod, means pivotally connecting the lever with each rod forreciprocating the rods and adapted for locking the rods relatively tothe guide bar when the lever is in brake release position, and adjustingmeans associated with each rod and the housing and adapted forincreasing the effective length of the spreader upon abnormal strokes oithe lever.

9. A slack adjuster for brake rigging for railway cars comprising alever having a normal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a housing upon the spreader, aholding piston rod slidably mounted upon the housing in a line parallelwith the length of the spreader, a cross-head pivotally connecting thelever with said rod, a guide upon the housing and having an elongatedslot occupied by the cross-head, an adjusting piston rod slidablymounted upon the housing in a line inclined obliquely to the holdingrod, a bearing head upon the adjusting rod, a fulcrum pin pivotallyconnecting the lever with said head, a guide bar having a bearingsurface extending parallel with the i adjusting rod and upon whichsurface said head is adapted to be locked by the lever when in brakerelease position, said head having an elongated slot adapted to permitthe fulcrum pin to move with the lever to brake applying position, and

adjusting means associated with each rod and the housing and adapted forincreasing the effective length of the spreader upon abnormal strokes ofthe lever.

l0. A slack adjuster for brake rigging for railway cars comprising alever having a normal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a housing upon the spreader, apair of pawls located within the housing, means engaged by the pawlsadapted for adjustably connecting the spreader with the lever andadapted for automatically taking up slack in the rigging upon anabnormal stroke of the lever, a pin rotatably mounted upon the housingand upon which pin said pawls are rotatably mounted for normaloperation, cooperating means upon the pin and said pawls adapted forsimultaneously disengaging the pawls from said first named means by therotation of said pin, and means upon said pin and located without thehousing adapted for rotating the pin.

ll. A slack adjuster for brake rigging for railway cars comprising alever having a normal stroke for the operation of the brakes, a spreaderoperatively associated with the brakes, a

and having one end thereof projecting beyond the latter, a cross-headpivotally connecting said end or the rod with the lever, rack teeth uponsaid rod, a pin rotatably mounted upon the spreader, a pawl pivotallymounted upon the pin THOMAS JAMES, JR.

holding V piston rod slidably mounted upon the spreader

